The present invention relates to an apparatus and a method for reducing oxygen content in a boiler exhaust gas.
It has been a conventional practice to press nitrogen gas into an oil field to maintain the pressure of an oil reservoir or to dissolve nitrogen gas in oil to form a so-called miscible condition, thereby heightening the fluidity of the oil in an oil reservoir.
Here, as a nitrogen gas source, nitrogen gas separated from oxygen by the low temperature processing of air is employed. The separation of nitrogen gas, however, requires a tremendous power and furthermore, the cost of the apparatus is markedly high.
There is accordingly a demand for countermeasures for obtaining nitrogen gas at a low power and a low cost.
An object of the present invention is therefore to provide an apparatus and a method for reducing oxygen content in a boiler exhaust gas, which makes it possible to prepare nitrogen gas at a low power and a low cost.
In accordance with the present invention, the above-described object is attained by an apparatus for reducing oxygen content in a boiler exhaust gas, which comprises a combustion catalyst portion disposed downstream or at the intermediate portion of a convectional heat transfer portion of a boiler and a fuel supply apparatus for supplying an oxygen reducing fuel to a position just before said catalyst combustion portion.
The present invention includes a method for reducing oxygen content in an exhaust gas from a boiler, which comprises supplying an oxygen reducing fuel to the exhaust gas at just before a combustion catalyst portion disposed downstream or at the intermediate portion of a convectional heat transfer portion of the boiler, burning said oxygen reducing fuel at said combustion catalyst portion to increase CO2 content and reduce oxygen gas content, to thereby obtain an exhaust gas which is composed mainly of nitrogen gas with an oxygen gas concentration not greater than 1,000 ppm.